Konta lost the opening set having held a 4-0 lead but recovered impressively, showing the significant improvements she has made on the surface this season.

Her only previous victory over a top-10 player on clay came against Roberta Vinci at the same venue three years ago.

Konta has had by far her best season on clay, reaching the final in Rabat earlier this month and now progressing to the last eight of one of the WTA Tour's biggest events.

Williams did not have to play twice, having been given a walkover in the second round by her sister Serena, and it was clear from the start of Thursday's match that she, too, was experiencing physical issues.